Re: Mail server and iptables/exim
Op vr 10-01-2003, om 05:19 schreef David P James:
> Nathan E Norman was roused into action on 2003-01-09 22:22 and wrote:
> > On Thu, Jan 09, 2003 at 09:48:41PM -0500, Stephen Gran wrote:
> >
> >>This one time, at band camp, David P James said:
> >>
> >>>>As you have noted, there are quite a few variables. Rule out iptables
> >>>>and tcpwrappers first - from an address outside the LAN, telnet
> >>>>your.host.ip 25 - if the connection times out, it's probably iptables,
> >>>>if it's refused, it's either iptables or tcpwrappers. If you connect
> >>>>and get the exim greeting banner, then you know that the problem is your
> >>>>exim.conf.
> >>>
> >>>I sshed to my brother's Redhat server and did the telnet my.host.ip 25
> >>>thing back to my server; the connection timed out. I tried a few other
> >>>ports (21, 80, 22, 110) and got a connection quite quickly.
> >>
> >>Then apparently iptables is DROPping connections to that port - fix that
> >>and we'll move from there.
> >
> >
> > Jumping in late, but isn't it also possible that the OP's ISP is
> > blocking port 25 (a common spam-fighting technique) ?
> >
>
> That's possibly it... That would also explain why I can get to the
> server's port 25 from behind the firewall, though I can get to it's port
> 25 on the external interface from behind the firewall as well. I'm
> reading conflicting reports as to whether or not Cogeco here in Kingston
> actually blocks port 25.
>
> --
> David P. James
> 4th Year Economics Student
> Queen's University
> Kingston, Ontario
> http://members.rogers.com/dpjames/
>
> The bureaucratic mentality is the only constant in the universe.
> -Dr. Leonard McCoy, Star Trek IV
I had something similar when setting up my server and the ssh service.
My isp blocks anything under 1024. So if i want to setup ssh i cannot
use port 22 on my server but have to use another port > 1024.
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